A communication system typically includes a transmitter for transmitting a data signal through a communication channel to a receiver of the communication system. In one type of communication system, the transmitter generates a data signal synchronized to a transmit clock signal and transmits the data signal to the receiver. In turn, a clock recovery circuit in the receiver reconstructs the transmit clock signal from the data signal. The receiver then extracts data from the data signal by using the reconstructed clock signal. In this type of communication system, the clock recovery circuit is often complicated which tends to reduce the manufacturing yield of integrated circuits devices containing the receiver. Moreover, the receiver consumes a considerable amount of area and power in an integrated circuit device because the receiver includes the clock recovery circuit.
In another type of communication system, the transmitter transmits a differential data signal and a differential clock signal to the receiver of the communication system. In turn, the receiver extracts data from the differential data signal by using the differential clock signal. Because the receiver does not have a clock recovery circuit in this type of communication system, circuitry in the receiver is less complicated than the circuitry of a receiver including a clock recovery circuit. As a result, the manufacturing yield of integrated circuit devices containing the receiver tends to be higher than those integrated circuit devices containing clock recovery circuits. Moreover, the receiver without the clock recovery circuit consumes less area and power in an integrated circuit in comparison to a receiver including a clock recovery circuit.
Although the receiver in this type of communication system is less complicated and consumes less area and power in an integrated circuit in comparison to receivers in other types of communication systems, the differential clock signal is susceptible to common-mode noise which may cause jitter in a single-ended clock signal generated by the receiver from the differential clock signal. As a result of the jitter in the single-ended clock signal, the receiver may generate data errors by incorrectly extracting data from the data signal. Moreover, the error rate of the receiver generally increases as the frequency of the differential clock signal increases because the jitter in the single-ended clock signal also increases. Therefore, it is desirable to reduce the common-mode noise in the differential clock signal to minimize the data error rate of the receiver.
In light of the above, a need exists for an improved system and method of reducing common-mode noise in a differential clock signal.